The present invention relates to adsorption apparati and more specifically to a modular adsorber cell for housing particulate adsorbent material therein which prevents by-pass of gas or vapor flowing therethrough.
The removal of a sorbable component from a gas or vapor stream by flowing such stream through a body of adsorbent material is a fundamental engineering practice. In the removal of a gaseous radioactive material from the atmosphere of nuclear reactor installations or other facilities which handle gaseous streams containing radioactive materials, conventional commercial adsorber cells typically are of two distinct forms. The first form is known as a dual-pleated form which utilizes continuous perforated plates for containing the particulate adsorbent material. The second form consists of individual slab-shaped units which typically are constructed from two solid sidewalls attached to a top and a bottom perforated metal plate. Within this structure a pair of parallel, spaced-apart inner perforated plates are disposed by attachment to the two solid sidewalls which also support such inner perforated plates. Adsorbent material is packed in the two outer-defined compartments and is retained therein by suitably designed end plates. The gas or vapor stream containing the sorbable radioactive component to be removed is flowed from the exterior of the cell through the beds of particulate material and thence into the empty chamber formed by the two inner perforated plates which empty chamber is connected to an outlet header for removal of the cleaned stream.
The slab-shaped units suffer many disadvantages. Because the two inner plates extend completely to, and are joined to, the supportive solid sidewalls, there is by-passing or short circuiting of the contaminated gas stream along the surface of such sidewalls directly to the interior outlet chamber of the unit. Thus, some of the incoming stream is not sufficiently contacted by the adsorbent medium for removal of the sorbable component therefrom. Such by-passing or channeling of the gas stream results because the packing density of the particulate adsorbent material is much less against the smooth flat metal surface of the supportive sidewalls than the packing density of the particulate medium against itself. Accordingly, the gas flow path along the solid supportive sidewalls provides less resistance to the stream to be cleaned (a lower pressure drop) resulting in a significant portion of the gas stream following such path and by-passing the adsorbent material. A disadvantage from which both the slab-like and the dual-pleated units suffer is the necessity for all structural members of these units to be joined by seam welds to further reduce by-passing of the gas stream through the units. The use of seam welds to construct these units is an expensive manufacturing technique, especially when compared to use of other joining techniques such as, for example, spot welding, pop-riveting, and the like.
These and many other disadvantages inherent in prior adsorber units or cells are overcome by the specific design of the modular adsorber cell of the present invention.